A machine apparatus that operates in a manner simulating operation of a human being by electric or magnetic effect is referred to as a “robot”. The origin of the term robot is said to be the Slavic word “ROBOTA (slave machine)”. In Japan, robots began to be commonly used in the late 1960s, and most of the robots were industrial robots for allowing automated and unmanned production works at factories, such as manipulators and carrier robots.
Recently, researches and developments relating to structures and stable gait control of legged mobile robots, such as pet robots that simulate physical mechanisms and operations of quadrupedal animals such as dogs, cats, and bears, and “humanoid” robots that simulate physical mechanisms and operations of bipedal orthograde animals such as human beings and monkeys, are in progress, and expectations for practical use have been raised. Although these legged mobile robots are less stable and suffer difficulty of attitude control and gait control compared with crawler robots, the legged mobile robots are advantageous in that flexible walking and running operations such as going up and down stairs and overcoming hurdles can be achieved.
An installed robot that is installed at a particular place, such as an arm robot, operates only in a fixed, local workspace, for example, for assembly and selection of parts. On the other hand, a mobile robot operates in an unlimited workspace; it is capable of freely moving along a predetermined path or without a particular path and performs a predetermined or arbitrary human task, and providing various services on behalf of a human, a dog, or other creatures.
A use of legged mobile robots is to perform various difficult tasks in industrial activities, production activities, etc. on behalf, for example, dangerous and difficult tasks such as maintenance work in nuclear power generation plants, thermal power generation plants, or petrochemical plants, transfer and assembly of parts in manufacturing factories, cleaning in high-rise buildings, rescue in fire sites, etc.
Another use of legged mobile robots is, rather than work assistance described above, closely related to life, i.e., “living together” with humans or “entertainment”. A robot of this kind reproduces rich emotions loyally using an operation mechanism of a relatively intelligent legged mobile animal such as a human being, a dog (pet), or a bear, or using for limbs. Furthermore, in addition to loyally exhibiting operation patterns input in advance, the robot is also required to express vivid responses dynamically in accordance with words and attitude (e.g., “praise”, “scold”, “strike”, etc.) of a user (or another robot).
In a conventional toy machine, relationship between user operations and responses is fixed, and operation of the toy cannot be modified in accordance with preference of a user. Thus, the user eventually becomes tired of the toy repeating the same operation.
In contrast, an intelligent robot that operates autonomously is capable of recognizing information of external environment and reflecting the information on its own behavior. That is, the robot determines its behavior by changing emotion model and instinct model based on input information such as sound, image, and sense of touch, thereby achieving autonomous thinking and operation control. That is, by preparing emotion models and instinct models, the robot is allowed to achieve realistic communication with humans at a higher level of intelligence.
In order to allow the robot to behave autonomously in accordance with change in environment, conventionally, behavior has been described by combinations of simple behavior descriptions such that a behavior is taken in response to information of an observation result. By mapping inputs to behaviors, functions such as randomness, internal status (emotion and instinct), learning, and growth are introduced, allowing expression of non-uniform, complex behaviors.
According to the, simple method of behavior mapping, however, for example, when a ball is lost from vision even for an instant during an operation of tracking and kicking the ball, since information regarding the ball is not held, a behavior for find the ball from scratch must be taken. Thus, recognition results are not used consistently.
Furthermore, the robot must determine which recognition result is associated with which result of previous observation when a plurality of balls is observed. Furthermore, in order to use more complex recognition results such as recognition of a face, recognition of flesh color, and recognition of voice, the robot must determine which flesh-colored region is a face and corresponds to which person, which person has uttered this voice, etc.